ardupilot/libraries/AP_HAL_Linux/I2CDriver.cpp

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#include <AP_HAL.h>
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#if CONFIG_HAL_BOARD == HAL_BOARD_LINUX
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#include "I2CDriver.h"
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <unistd.h>
#include <stdio.h>
#include <sys/ioctl.h>
#include <linux/i2c-dev.h>
#ifndef I2C_SMBUS_BLOCK_MAX
#include <linux/i2c.h>
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#endif
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using namespace Linux;
/*
constructor
*/
LinuxI2CDriver::LinuxI2CDriver(AP_HAL::Semaphore* semaphore, const char *device) :
_semaphore(semaphore),
_fd(-1),
_device(device)
{
}
/*
called from HAL class init()
*/
void LinuxI2CDriver::begin()
{
if (_fd != -1) {
close(_fd);
}
_fd = open(_device, O_RDWR);
}
void LinuxI2CDriver::end()
{
if (_fd != -1) {
::close(_fd);
_fd = -1;
}
}
/*
tell the I2C library what device we want to talk to
*/
bool LinuxI2CDriver::set_address(uint8_t addr)
{
if (_fd == -1) {
return false;
}
if (_addr != addr) {
ioctl(_fd, I2C_SLAVE, addr);
_addr = addr;
}
return true;
}
void LinuxI2CDriver::setTimeout(uint16_t ms)
{
// unimplemented
}
void LinuxI2CDriver::setHighSpeed(bool active)
{
// unimplemented
}
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uint8_t LinuxI2CDriver::write(uint8_t addr, uint8_t len, uint8_t* data)
{
if (!set_address(addr)) {
return 1;
}
if (::write(_fd, data, len) != len) {
return 1;
}
return 0; // success
}
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uint8_t LinuxI2CDriver::writeRegisters(uint8_t addr, uint8_t reg,
uint8_t len, uint8_t* data)
{
uint8_t buf[len+1];
buf[0] = reg;
if (len != 0) {
memcpy(&buf[1], data, len);
}
return write(addr, len+1, buf);
}
/*
this is a copy of i2c_smbus_access() from i2c-dev.h. We need it for
platforms with older headers
*/
static inline __s32 _i2c_smbus_access(int file, char read_write, __u8 command,
int size, union i2c_smbus_data *data)
{
struct i2c_smbus_ioctl_data args;
args.read_write = read_write;
args.command = command;
args.size = size;
args.data = data;
return ioctl(file,I2C_SMBUS,&args);
}
uint8_t LinuxI2CDriver::writeRegister(uint8_t addr, uint8_t reg, uint8_t val)
{
if (!set_address(addr)) {
return 1;
}
union i2c_smbus_data data;
data.byte = val;
if (_i2c_smbus_access(_fd,I2C_SMBUS_WRITE, reg,
I2C_SMBUS_BYTE_DATA, &data) == -1) {
return 1;
}
return 0;
}
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uint8_t LinuxI2CDriver::read(uint8_t addr, uint8_t len, uint8_t* data)
{
if (!set_address(addr)) {
return 1;
}
if (::read(_fd, data, len) != len) {
return 1;
}
return 0;
}
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uint8_t LinuxI2CDriver::readRegisters(uint8_t addr, uint8_t reg,
uint8_t len, uint8_t* data)
{
if (_fd == -1) {
return 1;
}
struct i2c_msg msgs[] = {
{
addr : addr,
flags : 0,
len : 1,
buf : (typeof(msgs->buf))&reg
},
{
addr : addr,
flags : I2C_M_RD,
len : len,
buf : (typeof(msgs->buf))data,
}
};
struct i2c_rdwr_ioctl_data i2c_data = {
msgs : msgs,
nmsgs : 2
};
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// prevent valgrind error
memset(data, 0, len);
if (ioctl(_fd, I2C_RDWR, &i2c_data) == -1) {
return 1;
}
return 0;
}
uint8_t LinuxI2CDriver::readRegistersMultiple(uint8_t addr, uint8_t reg,
uint8_t len,
uint8_t count, uint8_t* data)
{
if (_fd == -1) {
return 1;
}
while (count > 0) {
uint8_t n = count>8?8:count;
struct i2c_msg msgs[2*n];
struct i2c_rdwr_ioctl_data i2c_data = {
msgs : msgs,
nmsgs : (typeof(i2c_data.nmsgs))(2*n)
};
for (uint8_t i=0; i<n; i++) {
msgs[i*2].addr = addr;
msgs[i*2].flags = 0;
msgs[i*2].len = 1;
msgs[i*2].buf = (typeof(msgs->buf))&reg;
msgs[i*2+1].addr = addr;
msgs[i*2+1].flags = I2C_M_RD;
msgs[i*2+1].len = len;
msgs[i*2+1].buf = (typeof(msgs->buf))data;
data += len;
};
if (ioctl(_fd, I2C_RDWR, &i2c_data) == -1) {
return 1;
}
count -= n;
}
return 0;
}
uint8_t LinuxI2CDriver::readRegister(uint8_t addr, uint8_t reg, uint8_t* data)
{
if (!set_address(addr)) {
return 1;
}
union i2c_smbus_data v;
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memset(&v, 0, sizeof(v));
if (_i2c_smbus_access(_fd,I2C_SMBUS_READ, reg,
I2C_SMBUS_BYTE_DATA, &v)) {
return 1;
}
*data = v.byte;
return 0;
}
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uint8_t LinuxI2CDriver::lockup_count()
{
return 0;
}
#endif // CONFIG_HAL_BOARD